GUATEMALA CITY Thousands gathered in the main square of Guatemala's capital on Saturday to protest against corruption after a wave of graft scandals prompted a Cabinet shake-up and the resignation of the vice president. Many of the demonstrators' placards called for President Otto Perez to also step down; others urged a crackdown on political corruption and crime - demands echoed in similar protests in other Guatemalan cities."We don't want Otto Perez in power any more," said dentist Otto Chojolan amid the crowd in Constitution Square. "They've stolen so much money, and that's w...